1. Field
The present disclosure relates to an electric pump, and more particularly, to an electric pump pumping a fluid through a rotor rotated by a motor.
2. Background
In general, electric oil pumps (EOP) are devices for supplying, using a motor, oil to an oil pressure line in a transmission or a braking device of a vehicle in which an oil circulation is required.
In the case of hybrid electric vehicles (HEVs), since an engine is halted when a vehicle is not travelled, it is difficult to supply a predetermined pressure to a transmission through a mechanical oil pump. Due to this, an electric oil pump which supplies oil through a motor is used in the HEVs.
In the case of such an electric oil pump, a pump, a motor, and an inverter are separately manufactured, the pump and the motor are fastened by bolts, and the inverter is connected to the motor and the pump by means of separate cables. Therefore, the existing electric oil pumps are disadvantageous in that there are many wasteful factors in terms of a performance, efficiency and a manufacturing cost.
Meanwhile, in order to improve fuel efficiency of a vehicle, a two-stage electric pump composed of a pump supplying low-pressure fluid and a pump supplying high-pressure fluid has been proposed to minimize power which may be necessarily consumed. At this time, each pump in the above two-stage pump is completely separated from the motor, the number of components is increased, a volume of the electric pump and a manufacturing cost are increased.